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Of course it's not going to say anything - that is something calculated at the time you fly. You brought up the fact that crews wanted to launch 10 miles closer to target. Based on the flight manuals original numbers, that would have given crews an extra 30 minutes in the air (as I earlier pointed out). Also be aware that if the use of this torpedo affected aircraft performance that greatly, there would have been a change to the flight manual.

I'm looking for a FM manual reference right now...

Here's some more info showing a ~130 knots speed:
Tillman, U. S. Navy Dive and Torpedo Bombers of World War II, p58.

I'm with Joe on this one. A Dawn Like Thunder - The True Story of Torpedo Squadron Eight by Robert Mrazek which is probably the definitive book on the squadron states there were no hits made as well. Most of the data in the book was pulled from the official log of the unit.

I was referring to the Admiral who authored the post in the blog referencing Ensign Gay's account. I can understand why you may have thought I was referring to Ensign Gay, though.

OK, Fletcher was there, 3-6 June 1942, as was Ensign Gay, and this is his account. I'll even say why it makes sense to me. That torpedo squadron was the first wave on that task force and these fleet-class carriers are hard to miss with a torpedo coming off the belly of a plane flying that low to the water. This account could be wrong, and I'll acknowledge it's not the popular account. At any rate, here it is...

"Without a fighter escort, all 15 TBD Devastators of VT-8 were shot down by hordes of Zeros before they could inflict a hit. The suicidal mission was described by one writer as "equivalent to a stone thrown into a group of pigeons." VT-6 followed Waldron's lead but met a similar fate, without a single torpedo finding its mark. Most of their Mark 13 aircraft torpedoes traveled beneath the targets, and their detonators failed to explode or simply fell apart in the water. (It would take U.S. Navy experts several months to correct the defects in the Mark 13, during which time scores of airmen would lose their lives in vain.)"

FLYBOYJ, look out your window. Do you see that young boy going by on his bicycle with that cellphone stuck in his ear? Fifteen minutes ago he posted the start-up instructions for a Boeing 747 on Wikipedia.

Probably the definitive book on Midway is "Shattered Sword." The book is largely based on Japanese records many heretofore unused. The next best reference is probably "The First Team" by Lundstrom who is referenced often in "Shattered Sword." According to those sources none of the US VTs at Midway got a hit. Many never even got to launch the torps. If one has not read Lundstrom and "Shattered Sword" one is behind the curve and relatively uninformed.

When carrier launched strikes by both sides in daylight have great difficulty or even fail to locate the opposite side's ships how does it work that a night attack especially by AC that can barely go faster than a carrier at flank speed can succeed? At Coral Sea the IJN was behind a weather front that greatly hindered the US AC in finding them.

However I have at long last become convinced that the Stringbag was a war winning AC. I now wonder why the RN did not dust off HMS Victory. Victory would have been a superb stealth warship because her radar signature would be almost negligible since she was mostly wood. Her slow speed would have increased the accuracy of her guns. The Italians would have never detected her approach because she was so quiet and even if they detected her they would have thought they were seeing a mirage.. She could have gallivanted around the Med for months without being replenished which was a weak point of the RN. The FAA might have even cleared her spar deck and launched Swordfishs from her. Just kidding

When carrier launched strikes by both sides in daylight have great difficulty or even fail to locate the opposite side's ships how does it work that a night attack especially by AC that can barely go faster than a carrier at flank speed can succeed? At Coral Sea the IJN was behind a weather front that greatly hindered the US AC in finding them.

For a night strike to work against a moving target, the carier needed a daylight position of last known course and speed of the target. This happened to also be a necessary requirement for the raid into ports. Later, from 1941, the Brits had several aircraft in the squadron fitted with ASVII or ASVIII radar. ASV II had a range of over 40 km unde3r the right conditions for a normal warship....against a small target like a U-Boat conning tower, it was much less relaible (ASV II was better) and range was a maximum of about 10 km. Against TF, the search a/c might have a range of 20-40km. Thats almost as good as a visual search. Since the Swordfish was rated as a TSR (Torpedo/Spotter/Recon) a/c, this might be seen as the recce element of its mission.

Radar could not really assist in the actual attack. Normally a squadron of 12-15 a/c might have 2-3 flare droppers, who also usually carried 3 or 4 250lb bombs. They were the pathfinders, and whilst there was an enormous variation in how they went about their jobs, typically they would climb to about 7000 feet and then drop the magnesium flares in a stick "downwind" of the ship, so that if there was any moonlight or dusklight, such light was coming over the top of the target so that it projected silhouette and therby increased its visibility, whilst at the same time decreasing the visibility of the main attack force. You could classify this part of the mission as the "Spotter" commponent of the TSR. The flare droppers would then try and co-ordinate their attacks with the main force, the torpedo bombers, by carrying out divebombing attacks against the target. If they were lucky and achieved a hit, it would hopefully cause a fire(s) on the ship, illuminating the target even more.

The Torpedo echelons were trained to close the range to 1000 yards or less and attack in waves, usually consisting of pairs or sometimes three aircraft flights. For a torpedo bomber thats virtually point blank range. The Ark Royals Swordfish closed to about 710 yards when they attacked the Bismarck, with the banking aircraft probably passing to within 300 yards of the battleship as they turned away. By the time the torps had completed their runs to the battleship, she was almost presenting her stern fully on to the attack, presenting as narrow a target as she could. Its a testament to the accuracy and stability of that squadron hit the rudder....a virtual bulls eye.

The probelem for the Bismarck, is that by turning away she did two things. Firstly she presented her rudder and screws to the attack, which were the only real vulnerable bits of the hull. secondly the rear flak batteries were being directed by an inferiro director that could not cope with the low speed of the attackers.

Bismarck is the most famous atack carried out at night, but there were literally hundreds of such attacks. The Axis was losing an average of 50000 tons of shipping a month, a lot of it was sunk by Swordfish equipped squadrons. Nuch was also sunk by Beaforts, also operating at night using the same basic techniques. Swordfish are credited with sinking well over 250000 tons of shipping in these night attacks, and with the sinking of at least 22.5 enemy subs, and probably as many as 40. Many of those were done at night and in poor weather, beginning with U-451 in November 1941. The first U-Boat sinking by a Swordfish in daylight was in April 1940, when U-64 was sunk by a Swordfish from Furious (I think it was Furious)

This all takes a well trained crew, and an aircraft set up for the purpose. Because operating at night in the late 30's and early 40's was an inherently dangerous activity, you dont want a particualalry twitchy High Performance a/c....you want docility and relaibility. The Swordfish had this in spades. I dont see why the TBD could not have done a similar job....its just that the USN over-estimated the types survivability in daylight and dismissed too quickly the potentialities of night strike The Americans could have trained their TBD crews

However I have at long last become convinced that the Stringbag was a war winning AC. I now wonder why the RN did not dust off HMS Victory. Victory would have been a superb stealth warship because her radar signature would be almost negligible since she was mostly wood. Her slow speed would have increased the accuracy of her guns. The Italians would have never detected her approach because she was so quiet and even if they detected her they would have thought they were seeing a mirage.. She could have gallivanted around the Med for months without being replenished which was a weak point of the RN. The FAA might have even cleared her spar deck and launched Swordfishs from her. Just kidding

Cheeky....I am sure that if Cunningham had been asked he would have found a use for the old ship.....

Last edited by parsifal; 07-16-2012 at 11:43 PM.

Fr President Clemenceau’s speech to the AIF 7th July 1918: “ we expected a great deal of (Australians)… We knew that you would fight a real fight, but we did not know that from the beginning you would astonish the whole continent. I shall go back and say to my countrymen “I have seen the Australians, I have looked in their faces …I know that they will fight alongside of us again until the cause for which we are all fighting is safe for us and for our children”.

Might be appropriate to post some information on ASV radar, which was such an integral part of the Stringbags success

This is not my work, it comes straignt from the U-Boat net site. For some reason it fails to mention when the various radars were fitted to the Stringbag.....I do know that they (ASVIIs) were fitted to some aircraft from the beginning of 1941.

The USN had access to radar via the tizard mission from 1940. they had at least as much time to acquaint themselves with its potentialities from that time, which was aas longas the RN had for most of its formations. It embraced radar for its warships very strongly, but virtually ignored airborne radars until 1942, and were not in a position to use it for carrier aircraft really until 1944. The question begs....why????

British ASV radars

prepared by Emmanuel Gustin

Early Experiments
ASV Mk.I

When radar was developed in Britain in the late 1930s it was clear that any airborne radar had to be vastly different from the gigantic "Chain Home" radar masts that gave early warning to Britain's fighter defense. A dipole antenna operates best when its length is half the wavelength of the radar beam, and to direct the beam in any direction a large array of dipoles is required. Obviously, the number and length of the dipoles would be very limited in an airborne installation. However, at that time there was no sufficiently powerful source of short waves. To be useful, an airborne radar also needed to have a short minimum range, that is, it had to guide the aircraft close enough for its crew to see the target. This could be achieved by using shorter pulses than land radars.

There was little difference, at that time, between the development of AI (airborne intercept, i.e. radar for nightfighter) and ASV (airborne surface vessel, radar for maritime patrol aircraft). In 1938 and 1939, ASV radar had the higher priority.

On 17 August 1937, the very first British airborne radar was flown. Based on the Western Electric 316A valve, it generated 100 Watts of power at a wavelength of 1.25 meters, and was later improved by increasing the wavelength to 1.5 meters. Installed in Avro Anson K6260, this radar proved that it was capable of tracking the aircraft carrier HMS Courageous, the battleship HMS Rodney, and the cruiser HMS Southampton, in weather conditions that would have made conventional reconnaissance impossible. It even detected aircraft taking off from HMS Courageous.

The radar was not yet ready for service, however. Development was delayed by what Dr E.G. "Taffy" Bowen, head of the airborne radar group, described as "totally inadequate resources and virtually no administrative back-up." Finally, two antenna configurations were developed for ASV radar. One used a dipole transmitting antenna with a reflector to give a broad beam in the forward direction. The two receiving antennas were on the aircraft's wings, and their polar diagrams overlapped. The direction of the target was determined by comparing the signals from the two receivers, displayed together on a cathode-ray tube, one to the left of the (vertical) baseline and the other to the right. If the target was on the right then the right receiver gave the stronger signal. The vertical timebase indicated the distance to the target. This system gave a range of 10 miles on a 1000 ton ship, and up to 40 miles on a coastline with steep cliffs.

This was introduced as the first ASV radar (Mk.I), and installed on the Hudsons of Coastal Command. By the end of 1940 it was fitted in 24 Hudsons and 25 Sunderlands. About 200 sets were produced. Experience with it was not very good. The radar was unreliable and new equipment, and the manufacturing standard of many components left a lot to be desired. The problems of maintenance and training were enormous. Its usefulness and popularity were increased by Sqdn. Ldr. Lugg, who installed a 1.5 meter beacon at Leuchars. ASV Mk.I then was, at least, useful navigation equipment.

ASV Mk.I was not intended to detect submarines, but after an enquiry from admiral Somerville in late 1939 test were conducted with one of the Hudsons of No.220 Sqdn and the submarine L 27. It was demonstrated that, flying at 1000 feet, the submarine could be detected at 3 miles, broadside on, and this under experimental conditions --- that means that the crew of the Hudson knew exactly where the submarine was. Further tests revealed that when flying at 6000 feet, the range was increased to 6 miles.

A notable improvement was achieved with what called Long Range ASV. LRASV was based on the second antenna configuration developed. It was a sideways-looking system. The transmitter was an array of ten dipoles, installed in five (later reduced to four) pairs on top of the fuselage of the aircraft. The receiving antennas were Sterba arrays, fitted to the sides of the fuselage. Because the transmitter array was a dipole array 18 feet long and the two receivers were arrays 12 feet long, a much better resolution and range could be achieved. The first installation was on a Whitley bomber, in late 1939. LRASV had a range 2.5 times better than the forward-looking system; it could detect submarines at 10 to 15 miles.

ASV Mk.II

Developed at the Royal Aircraft Establishment at Farnborough in early 1940, ASV Mk.II differed from Mk.I mainly because it was properly engineered, and therefore much more reliable. Although called a 1.5m radar, it actually used 1.7m (176MHz). Range was up to 36 miles. The minimum range was about a mile. Several thousand sets were built, and installed in Hudsons, Sunderlands, Wellingtons, Beauforts, Warwicks, Whitleys, Liberators, and other Coastal Command aircraft. ASV Mk.II was used with both the forward-looking and the sideways-looking LRASV configuration, production being divided approximately equal. Only the LRASV was useful against submarines.

The first success was recorded on 30 November 1940, when a Whitley Mk.VI equipped with ASV damaged U-71 in the Bay of Biscay. By mid-1941 the ASV radar had increased daytime attacks on U-boats by 20%, and made nightly attacks possible.

However, night attacks were generally ineffective, for the simple reason that the aircraft crew could not see the submarine. The radar guided them to a mile of the submarine, but not closer. On 21 December 1941 an ASV-equipped Swordfish made the first successful night attack on an U-boat, but such remained exceptions.

ASV Mk.III

By late 1942, the U-boats carried "Metox", a simple radio receiver, which enabled them to detect the ASV Mk.II radar. This reduced the efficiency of the ASV equipped aircraft considerably, and shipping losses increased again.

The history of ASV Mk.III is rather complicated. Because of personal conflicts, the original group that had developed airborne radar was dispersed. A new team was formed, tasked with the development of centimetric AI radar for nightfighters. The big advantage of a centimetric radar is that the beam can be directed accurately by a relatively small paraboloid reflector. This offered better range and resolution and eliminated the strong ground returns, which were unavoidable with the broad beams of the 1.5 meter radar sets. Centimetric radar was made possible by the development, by J.T. Randall and H.A.H. Boot, of the cavity magnetron. The first was tested on 21 February 1940. By June 1940, GEC had produced the first sealed magnetrons, suitable for use in aircraft.

Development concentrated on AI for nightfighthers, but in the autumn of 1940 the 10cm radar attracted naval interest, represented by Captain B.R. Willett and C.E. Horton. It was demonstrated to them that the ground-based, experimental radar equipment could track ships. On 11 November tests were conducted with the submarine HMS Usk, which was tracked at 7 miles. Some time was spent refining the equipment and defining the antennas, until a cylindrical paroboloid section was chosen for shipboard installations. By March 1941, a fully engineered 10cm radar was on board of the corvette HMS Orchis, and on 16 November 1941 the sinking of U-433 near Gibraltar was attributed to the "Type 271" 10cm radar. By May 1942, 236 ships carried centimetric radar.

Meanwhile, the development of centimetric AI had continued, and in March 1942 it entered operational service. Known as AI Mk.VII, this was a remarkable achievement, and by August 1942 a fully-engineered production model followed, AI Mk.VIII. Tests against submarines had been conducted in April 1941, against HMS Sea Lion, and in August, against HMS Sokol. The radar was effective, but development of the ASV version was slow, much slower than that of AI radar, and the first experimental, centimetric ASV radar was not test flown before December 1941. By the summer of 1942 this so-called ASVS radar was being productionized by Ferranti. But then, on 30 September 1942, Ferranti was told to halt the work. Work on ASVS was stopped, much to the dismay of Coastal Command.

Fr President Clemenceau’s speech to the AIF 7th July 1918: “ we expected a great deal of (Australians)… We knew that you would fight a real fight, but we did not know that from the beginning you would astonish the whole continent. I shall go back and say to my countrymen “I have seen the Australians, I have looked in their faces …I know that they will fight alongside of us again until the cause for which we are all fighting is safe for us and for our children”.

The reason for this decision was that at the same time, H2S ground-mapping radar was under development for Bomber Command. The two systems had many similarities, and H2S was closer to production. The first test of a ground-mapping centimetric radar had been made on 1 November 1941, and was impressively succesful. A more practical system was flying in a Halifax on 17 March 1942, and immediately attracted the attention of a endless parade of high-ranking officers. This culminated in meeting on Downing Street 10 on 3 July, where Churchill insisted that he wanted 200 sets operational by mid-October. At that time, there was no working H2S radar at all, because the Halifax had crashed. There were still considerable problems in designing the H2S scanner, and it had not yet been resolved whether a cavity magnetron or a klystron would be used to generate the microwave power. The klystron provided insufficient power, but the use of the cavity magnetron meant that it would certainly fall in German hands. By 15 July, it had been decided to use the magnetron anyway. Development was enhanced by the valuable support of Sir Robert Renwick, appointed by Churchill to oversee H2S development, and by Group Captain D.C.T. Bennet, commander of No.8 Group, the "Pathfinder Force" of Bomber Command. By September, a version was ready for service trials. At the end of 1942, 24 bombers, Halifaxes and Stirlings, carried H2S.

Of course H2S Mk.I had been designed for four-engined bombers flying at 20,000 feet, and a hasty demonstration over sea was an annoying failure. Obviously, the system needed to be redesigned for operations at 2,000 feet. This did little to improve the attitude of Coastal Command towards this new radar system, which already suffered from being "not invented here". To some extent to irritation of Coastal Command was justified: There were to be fierce conflicts with Bomber Command over the allocation of radar equipment to H2S and ASV.

In any case, Coastal Command was not going to get any of the four-engined "heavies", so the first installation was made in a twin-engined Wellington bomber. The radar was installled in the nose, with the size of the scanner reflector reduced to 28 inches. This gave a 60 degree field of view in front of the aircraft. The display was the now familiar PPI (Plan Position Indicator), which presented a 'map view' of the relative positions. Coastal Command was still less than eager to support the system, and this slowed development. On 1 March 1943 a Wellington of No.172 Sqdn flew the first patrol over the Bay of Biscay. On 17 March they saw their first U-boat at 9 miles, but the Leigh light failed and the first attack was made on the next day. At the end of March 13 sightings had been made.

By May, Coastal Command detected and attacked most U-boats in the Bay of Biscay. U-boat sightings improved dramatically, and shipping losses decreased drastically, from 400,000 to 100,000 tons per month. Doenitz ordered his submarines to stay on the surface and fight it out with aircraft, but he lost 56 U-boats in April and May. Doenitz reported that the situation had become "impossible". This "temporary setback" was significant enough to be mentioned in a speech by Hitler. This result had actually been achieved by a handful of aircraft equipped with ASV Mk.III.

Meanwhile in the USA, a 10cm ASV radar called DMS-1000 had been developed by the Radiation Laboratory. It was installed in Liberators, but although the first one arrived in the UK in March 1942, it still lacked the Leigh light. The Liberator was used operationally in early 1943, and by the summer the Liberators were closing the "Atlantic gap". Everywhere in the Atlantic, U-boats could now be attacked by ASV-equipped aircraft.

ASV Mk.VI

The British anticipated that the Germans would develop a warning detector for the 10cm ASV, as they had done for the 1.5 meter ASV. (They indeed did, the Naxos system, but it appeared three months after the first use of centimetric ASV radar. It seems that during the interrogation of a captured British officer, the Germans were told that the British were actually detecting the weak emissions of Metox. As this was technically possible, it was believed.)

Therefore ASV Mk.VI was developed. It was more powerful than Mk.III, but it had an attenuator (called Vixen) fitted. The idea was to reduce the power once the U-boat had been detected, so that the operator of any detection device would be fooled into believing that the aircraft was flying away, or at least not coming closer. Development of Mk.VI was once again slowed down by administrative obstructions. On 23 October 1943 Air Marshall Sir John Slessor, then head of Coastal Command, heard about this. Slessor was convinced that the Germans already had a detector for the 10cm radar (they had), and he reacted by writing a very angry letter in which called for disciplinary action, and used terms such as "crass stupidity" and "congenital idiot". Despite whispers about Slessor's imminent court-martial, this managed to create some activity in the Air Ministry. (Coastal Command lost the fight to get the 3cm ASV Mk.VII, however. All 3cm equipment was allocated to Bomber Command.)

There was also ASV Mk.VIA, which allowed the aircraft to lock onto the U-boat and aim its Leigh light directly at it. But this was not ready before the summer of 1944. The even more developed ASV MK.VIB made blind bombing possible.

ASV Mk.VII

The Mk.VII system was a development of a 3cm H2S system. This too was planned in anticipation of a German detector for 10cm waves. However, Bomber Command refused to accept any reduction in its deliveries of the 3cm H2S. When an agreement was reached to release some 3cm radars to Coastal Command, the commander of Bomber Command, A. Harris, telephoned Churchill and managed to reverse the decision. As a consequence, ASV Mk.VII had a low priority, and this decreased even more when the defeat of the U-boats became clear and the ports on the French coast were taken by Allied forces.

But in October 1944, the Allied became aware of two worrying developments: The appearance of a new class of U-boats, and the fitting of the "Schnorkel" to U-boats. The latter was virtually undetectable by 10cm ASV radar. In a meeting on 22 November, it was decided that developments of the 3cm ASV radar offered the best hopes, although experiments with 1.25cm radars were also conducted. The work was undertaken both in Britain, under the aegis of B.J. O'Kane, and in the USA, where the US Navy started the aptly called "Project Hawkeye" in the Radiation Laboratory of the MIT. However, the tests were not concluded before the end of the war.

ASV Mk.XI

The ASV Mk.XI was a centrimetric radar intended for the TBR (torpedo bomber and reconnaissance) aircraft of the Fleet Air Arm, the component of the Royal Navy that operated carrier aircraft. It was also known known as ASVX and therefore it sometimes has been called, erroneously, ASV Mk.X.

ASV Mk.XI could be fitted between the main wheel legs of a Fairey Swordfish. In addition to the bulky radome, a Leigh light could be fitted. The radome made the the carrying of torpedoes or large depth charges impossible, so when the target was a ship the Swordfish was accompanied by other aircraft without radar. Against submarines, the radar-equipped Swordfish Mk.III was armed with eight rockets on underwing launches, and also carried flares to illuminate any U-boat it found. Fired at 600 yards, the rockets easily penetrated a submarine's hull.

This radar was also carried by the Fairey Barracuda Mk.III.

ASV Mk.XI had a maximum range of about 60km against ships, and in good conditions and at low altitude (2000 feet) it could detect a surfaced submarine at about 20km. But it could detect a schnorkel only in very calm seas and at distances below 8km. It gave bearings with an accuracy of about 2 degrees.

Sources
•Avionics -- The Story and technology of aviation electronics
Bill Gunston, published by Patrick Stephens Limited, 1990.
•Boffin -- A Personal Story of the Early Days of Radar, Radio
Astronomy and Quantum Optics
R Hanbury Brown, published by Adam Hilger, 1991.
•Echoes of War -- The Story of H2S Radar
Sir Bernard Lovell, published by Adam Hilger, 1991.
•Wings of the Navy
Capt. Eric Brown, published by Pilot Press, 1980.
•Across the Ether
Stephen Pope, in Aeroplane Monthly, June 1995.
-> Article includes pictures of aircraft with ASV radar and a picture of the Leigh light.
•Brian Wood sent us information on the ASV Mk.XI radar from the original manual.

Fr President Clemenceau’s speech to the AIF 7th July 1918: “ we expected a great deal of (Australians)… We knew that you would fight a real fight, but we did not know that from the beginning you would astonish the whole continent. I shall go back and say to my countrymen “I have seen the Australians, I have looked in their faces …I know that they will fight alongside of us again until the cause for which we are all fighting is safe for us and for our children”.

This all takes a well trained crew, and an aircraft set up for the purpose. Because operating at night in the late 30's and early 40's was an inherently dangerous activity, you dont want a particualalry twitchy High Performance a/c....you want docility and relaibility. The Swordfish had this in spades. I dont see why the TBD could not have done a similar job....its just that the USN over-estimated the types survivability in daylight and dismissed too quickly the potentialities of night strike The Americans could have trained their TBD crews

The TBD was grossly overweight, underpowered and consequently had very poor range because the engine had to be run at high throttle settings to stay airborne. Adding ASV radar would have been nearly impossible and ultimately pointless because of the poor range. A Swordfish weighed about 8500lb, had 775hp and had 607 sq ft of wing area so it had lots of lifting capacity. The Albacore weighed about 10,500lb, had 1100hp and 623 sq ft of wing area. The TBD weighed 10,000lb+ (maybe as much as 11,000lb), had 900hp but only 422 sq ft of wing area or about the same as a Barracuda which weighed 14000lb but had 1640hp, and the Barracuda was considered underpowered!